Luba / Guides

How many chairs do you have free on a date? Avoid double booking your party rentals

We make Luba, the app in the “With Luba” boxes. The math, the formula and the tips work just as well without the app.

What you need: How many of each item you own, actually counted · Your bookings, with delivery and return dates and times · Paper, a spreadsheet or an app

1. Start with what you actually have

   The math starts with how many pieces you own in good shape. If you bought 200 chairs but 6 are broken and 2 are out for repair, you have 192. The broken ones you keep counting are the ones you’ll be missing on the day of the event.

   Every time a piece breaks or goes missing, take it off your list that same day. And every so often, do a real count: the number in your head is always higher than the real one.

   Note

   If pieces break often, keep a few spares and don’t promise them: with 200 chairs, for example, book up to 195. They save you when a customer returns late or something breaks during loading.

2. Subtract everything that’s out at that moment

   For the date you’re asked about, take two things off what you own:

   Every booking that overlaps that date: the ones going out that day, the ones coming back that day, and the ones that left before and come back after.

   Anything that was due back and isn’t: if a customer is late, you don’t have those pieces, even if their booking is over on paper.

   And watch the times. A booking coming back Saturday at noon collides with a delivery on Saturday at 10 AM, even though both are “Saturday.” If one comes back Friday night and the other goes out Saturday morning, you can use the same chairs, as long as you have time to count and clean them.

   An example with 200 folding chairs. Sarah wants 120 for Saturday, 10 AM to 10 PM:

   Emily has 80 chairs from Friday at 7 PM and brings them back Saturday at noon. At 10 AM on Saturday she still has them, so they count.

   David was supposed to bring back 20 chairs on Wednesday and hasn’t. They count too.

   Free for Sarah: 200 minus 80 minus 20, so 100. She wants 120: you’re 20 short.

   With Luba

   In Luba, tap an item in Things: at the top you see how many are free today and, under Coming up, every upcoming booking with how many stay free while it lasts, including what wasn’t returned on time (“Was due back…”) and what’s Pending.

   

3. For a multi-day order, look at the busiest moment

   When someone wants chairs from Friday to Sunday, do the math for each day (and each time of day when something changes) and go by the lowest number. That moment decides whether you have enough.

   Don’t add up every booking of the week: 30 chairs out on Saturday and 50 on Sunday are never out at the same time. For a Saturday-to-Sunday order, those bookings tie up 50 chairs at most, not 80. If you add them up, you turn down orders you could have taken.

4. Decide what to do with quotes

   A quote isn’t a booking: if you count it as out, you turn customers away for an order that may never come. But if you ignore it and it goes ahead, you’re short.

   The practical way is to write it down anyway, check whether you’d still have enough if it’s confirmed, and give it a deadline: “I’ll hold them until Thursday at noon.” Many rental companies only lock in the date once the customer pays a deposit. If another order comes in for the same date, check with the person who got the quote first.

   With Luba

   In Luba, a Pending booking works as a quote: it doesn’t hold anything, but if it overlaps another one, the app tells you, for example with “Fits, but 20 short if pending bookings are confirmed.”

5. Do the math on paper or with a formula

   On paper: one sheet per item, with a calendar. On each day, write how many go out and who has them. It works if you have a few bookings a week.

   In a spreadsheet: one row per booking, with the delivery date in column A, the return date in column B (dates only, no times) and the number of chairs in column C. This formula, in Excel or Google Sheets, adds up the chairs that are out on the date in cell H1:

   =SUMIFS(C:C, A:A, "<="&H1, B:B, ">="&H1)

   Subtract it from what you own. Keep in mind that it counts by day, not by hour, and it doesn’t see late returns: add those yourself. If you also track bookings that aren’t confirmed yet, add a status column so you can see both numbers.

6. If you’re short, say so before you promise

   Telling the customer right away beats letting them down on the day of the event. You have a few ways out:

   Offer what you have: 100 chairs often work just as well, or they fill in with their own.

   Another style: if you’re 20 folding chairs short, maybe you have 20 of another kind.

   Sub-rent from another company: if another rental business lends you the ones you’re missing, write them down as a booking of their own, so you remember to give them back.

   A text you can copy:

   “Hi Sarah, for Saturday I have 100 folding chairs available out of the 120 you need. Would 100 work, or should I fill in with 20 chairs in another style?”

   With Luba

   In Luba, while you write down the booking, the app shows how many are free on those dates. If you’re short, it tells you with “20 short on these dates” and offers Set 100, the ones you do have.